Monday, June 23, 2014

Load Composition

Figure 1. As the center of gravity
for the load moves forward, the lifting capacity for the forklift decreases.

The stated capacity of a
forklift only applies to the load center indicated on the data plate. If the
load is not centered at the specified position, the forklift's capacity will be
reduced. Loads come in all shapes and sizes, not just symmetrical
boxes. The load size, position, and weight distribution critically affect the
forklift's capacity and the stability
of the truck. Consider the following factors before engaging a load:

Figure 2. The same 4500 pounds weight loaded properly (top) will exceed the rated capacity of
4500 pounds if the rectangular box is positioned lengthwise (bottom).

Load weight, weight distribution, size, shape,
and position are key factors affecting the stability of the forklift.
Forklifts are
designed to carry a capacity load at a standard load center, commonly 24
inches.
This means that the forklift’s capacity was determined as if the load
were a
cube whose weight is evenly distributed (i.e., whose center of gravity
is
exactly in the center of the cube) and which is resting on a standard
pallet
having dimensions of 48 inches by 48 inches. With such a load, the
horizontal
distance from the center of the load to the vertical part of the forks
would be
24 inches. Of course, most loads are not perfectly shaped cubes having
their
center of gravity exactly in the middle of the cube. To the extent that
the load
differs from this theoretical load — such as if it is irregularly
shaped, has
unbalanced weight distribution, or is not centered on the forks — the
capacity
may be reduced.

Potential Hazards:

While arranging a load, be aware of the following:

tipover

Loss of steering control (Shifting too much weight forward raises the rear wheels.)

Falling load

Collision

Requirements and Recommended Practices:

Do not exceed the capacity of the forklift that appears on the forklift's
data plate (sometimes called the "nameplate"). If the load is oversized, irregularly shaped, or loaded incorrectly, the
actual load center distance could exceed the stated load center distance,
causing the truck's capacity to be exceeded. (Figure 2).

Always minimize the distance from the front wheels to the load center. Load a large rectangular box widthwise across the
forks of the truck as in Figure 2. Placing a large rectangular load lengthwise causes the load center to shift forward
further away from the front wheels, exceeding the truck's capacity and lifting the rear wheels off the ground.

Figure 3. The heaviest weight should be loaded as close to the masts as possible.

Load as close to the front wheels as possible to minimize the load center distance. Load the heaviest part toward the mast.
(Figure 3)

Position the load in a way that will shorten the load center distance.